Sandwiched gear train arrangement for multiple electric motor mixed-speed continuous power transmission

ABSTRACT

An electric powertrain includes a first electric motor that has an uninterrupted connection with a drive shaft of a vehicle. The electric powertrain further includes a first gear train that has an interruptible connection with the drive shaft. In one form, this interruptible connection includes a second carrier and a clutch engagement member. The electric powertrain further includes a sun gear in the form of a ring gear and planet gears in the form of a first output shaft. To provide a compact configuration, the first electric motor and the first gear train are sandwiched between the sun gear and the planet gears.

BACKGROUND

There has recently been an increased interest in hybrid and electricvehicles. However, the recent developments have mostly been related tothe consumer passenger vehicle market. The same technology has not yetbeen made available in the commercial vehicle marketplace. The currentelectric motors used in consumer vehicles are generally not able to beeasily retrofitted into commercial vehicles. Retrofitting the electricmotors into the powertrain would, in most cases, require a full redesignof the powertrain components. Furthermore, there is the issue of theloss of power during a shift in an electric vehicle. This issue would bemost prevalent in a heavy commercial vehicle as the loss of power willresult in vehicular deceleration that would be readily perceptible bythe driver.

Thus, there is a need for improvement in this field.

SUMMARY

A multiple electric motor system has been developed to address theissues mentioned above as well as other issues. In one form, the systemincludes dual electric motors that provide power to an output such as adriveshaft of a vehicle. One of the electric motors (“A”), which will bereferred to as the “first motor” for our purposes, is always connectedto the output drive shaft in order to continuously provide power forpropelling the vehicle. In other words, the first electric motor (A) hasan uninterrupted connection with the output. The system further includesa second electric motor (“B”) that intermittently applies torque to theoutput shaft. In one variation, this intermittent connection between thesecond electric motor (B) and the output includes at least one clutch.The clutch engages and disengages the second electric motor (B) with theoutput shaft.

To address the issue of retrofit due to space constraints, the firstelectric motor (A) and the second electric motor (B) are sandwichedbetween the first gear train and the second gear train. To put thisdifferently, one of the gear trains may be located upstream of bothmotors while the other may be located downstream from both motors, whereupstream is defined as opposite the direction of power transmission anddownstream is defined as in the direction of power transmission.Additionally, there may be a dog clutch located between the first andsecond electric motors. This clutch will serve to selectively couple thefirst and second output shafts and allow the second electric motor tocontribute to the output.

The sandwiched configuration allows for the overall size of thetransmission to be reduced. This reduction in size will allow for thetransmission to be retrofitted into commercial vehicles without the needfor a major redesign in the powertrain configuration.

Aspect 1 generally concerns a system that includes a first electricmotor connected to an output and a second electric motor connected tothe output.

Aspect 2 generally concerns the system of any previous aspect in whichthe first electric motor and the second electric motor are sandwichedbetween a first gear train and a second gear train.

Aspect 3 generally concerns the system of any previous aspect in whichthe first electric motor and the second electric motor both have aninterruptible connection to the output.

Aspect 4 generally concerns the system of any previous aspect in whichthe first electric motor has an uninterrupted connection to the outputand the second electric motor has an interruptible connection to theoutput.

Aspect 5 generally concerns the system of any previous aspect in whichthe interruptible connection includes a clutch configured to couple thesecond electric motor to the output.

Aspect 6 generally concerns the system of any previous aspect in whichthe clutch includes a positive clutch.

Aspect 7 generally concerns the system of any previous aspect in whichthe clutch has an actuator and a Selectable One-Way Clutch (SOWC).

Aspect 8 generally concerns the system of any previous aspect in whichthe clutch is located between the first electric motor and the secondelectric motor.

Aspect 9 generally concerns the system of any previous aspect in whichthe clutch is located downstream of the first electric motor and thesecond electric motor at the output.

Aspect 10 generally concerns the system of any previous aspect in whichthe second gear train is located upstream from the first electric motorand the second electric motor.

Aspect 11 generally concerns the system of any previous aspect in whichthe Selectable One-Way Clutch (SOWC) is located upstream from the firstelectric motor and the second electric motor at the second gear train.

Aspect 12 generally concerns the system of any previous aspect in whichthe second electric motor is located upstream relative to the firstelectric motor.

Aspect 13 generally concerns the system of any previous aspect in whichthe first gear train is located upstream from the first electric motorand the second electric motor.

Aspect 14 generally concerns the system of any previous aspect in whichthe Selectable One-Way Clutch (SOWC) is located upstream of the firstelectric motor and the second electric motor at the first gear train.

Aspect 15 generally concerns the system of any previous aspect in whichthe first electric motor is located upstream relative to the secondelectric motor.

Aspect 16 generally concerns the system of any previous aspect in whichthe first gear train includes a planetary gear.

Aspect 17 generally concerns the system of any previous aspect in whichthe first and second electric motors rotate about a common axis ofrotation.

Aspect 18 generally concerns a method of operating the system of anyprevious aspect.

Further forms, objects, features, aspects, benefits, advantages, andembodiments of the present invention will become apparent from adetailed description and drawings provided herewith.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a vehicle.

FIG. 2 is a diagrammatic view of an example of an electric powertrainthat can be used in the vehicle of FIG. 1.

FIG. 3 is a diagrammatic view of another example of an electricpowertrain that can be used in the vehicle of FIG. 1.

FIG. 4 is a cross-sectional view of the electric powertrain from FIG. 3.

FIG. 5 is a diagrammatic view of a further example of a transmissionthat can be used in the vehicle of FIG. 1.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

For the purpose of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended. Any alterations and further modificationsin the described embodiments, and any further applications of theprinciples of the invention as described herein, are contemplated aswould normally occur to one skilled in the art to which the inventionrelates. One embodiment of the invention is shown in great detail,although it will be apparent to those skilled in the relevant art thatsome features that are not relevant to the present invention may not beshown for the sake of clarity.

The reference numerals in the following description have been organizedto aid the reader in quickly identifying the drawings where variouscomponents are first shown. In particular, the drawing in which anelement first appears is typically indicated by the left-most digit(s)in the corresponding reference number. For example, an elementidentified by a “100” series reference numeral will likely first appearin FIG. 1, an element identified by a “200” series reference numeralwill likely first appear in FIG. 2, and so on.

A vehicle 100 according to one example is illustrated in FIG. 1. Asshown, the vehicle 100 includes at least one powertrain system 105, atleast one controller 110, and at least one Energy Storage System (“ESS”)115 configured to supply power to the powertrain system 105. Thepowertrain system 105, controller 110, and ESS 115 are operativelyconnected together so as to communicate with one another via at leastone Controller Area Network (“CAN”) 120. The controller 110 isconfigured to control the operation of one or more systems and/or othercomponents of the vehicle 100 such as the powertrain system 105 and ESS115. The powertrain system 105 has an output or drive shaft 125 thattransfers mechanical power from the powertrain system 105 to apropulsion system 130. In the illustrated example, the propulsion system130 includes one or more wheels 135, but the propulsion system 130 infurther examples can include other types of propulsion devices likecontinuous track systems. One or more power cables 140 transferelectrical power between the powertrain system 105 and the ESS 115.

The powertrain system 105 is designed to electrically propel the vehicle100 in an efficient manner. As will be explained in greater detailbelow, the powertrain system 105 is designed to power heavy-dutycommercial and/or military grade vehicles such as buses, garbage trucks,delivery trucks, fire trucks, and semi-trailers. The powertrain system105 is designed to electrically power vehicles 100 with a class grouprating of at least four (4) according to the US Department ofTransportation Federal Highway Administration (FHWA) classification ruleset. In one form, the powertrain system 105 is configured to move atleast 40,000 pound (18,144 Kg) passenger vehicles like buses. Thepowertrain system 105 has a unique, compact centerline design thatallows the powertrain system 105 to be easily retrofitted intopre-existing vehicle chassis designs and/or conventional drivetrainswith minimal changes to the other parts of the vehicle 100 like thebraking and suspension systems. This in turn allows existing internalcombustion type vehicles to be readily reconfigured as fully electricvehicles. Moreover, the centerline design of the powertrain system 105reduces gear loss and other power losses so as to make the vehicle 100more power efficient which in turn can improve driving range and/orreduce weight of other components such as the ESS 115.

FIG. 2 shows an electric powertrain 200 that can be used in the electricpowertrain system 105. The electric powertrain 200 includes a firstelectric motor 210 with a first inverter 212 and a second electric motor215 with a second inverter 217. In this illustrated example, the firstelectric motor 210 and second electric motor 215 are not the same typeof motor such that the first electric motor 210 and second electricmotor 215 are not interchangeable with one another. By using differenttypes of motors, which can have different speed, torque, and/or powercharacteristics, the efficiency and power characteristics of theelectric powertrain 200 can be enhanced. In other words, one of themotors can compensate for the deficiencies of the other under differentoperational demands. For instance, when the electric powertrain 200 isdealing with a load that requires high torques at low speeds, alow-speed, high-torque motor can provide most (if not all) of the power,and the corresponding high-speed, low-torque motor can provide lesspower. When the conditions reverse to a low torque, high speedsituation, the workloads of the motors can reverse such that thehigh-speed, low-torque motor provides more (or all) of the power, andthe low speed, high torque motor provides less power.

As shown, the first electric motor 210 is located upstream of the driveshaft 125 relative to the second electric motor 215. In the illustratedexample, the first electric motor 210 is a high speed electric motor,and the second electric motor 215 is a low speed electric motor. In oneversion, the first electric motor 210 is a high speed electric motorhaving a rated operating speed of at least 5,000 rpm, and the secondelectric motor 215 is a low speed electric motor having a ratedoperating speed of less than 5,000 rpm. The first electric motor 210 inone version has a rated operating speed of at least 10,600 rpm, a ratedpeak power of at least 250 hp, a rated continuous power of at least 150hp, a rated continuous torque of at least 240 lb-ft, and a rated peaktorque of at least 310 lb-ft. In this version, the second electric motor215 has a rated operating speed of at most 4,500 rpm, a rated peak powerof at least 250 hp (600 Volts DC), a rated continuous power of at least133 hp (600 Volts DC), a rated continuous torque of at least 320 lb-ft,and a rated peak torque of at least 735 lb-ft. The speed of the secondelectric motor 215 in one form is limited to a maximum speed of 3,500rpm during operation.

The first inverter 212 and second inverter 217 convert DC from the ESS115 to AC in order to power the first electric motor 210 and secondelectric motor 215, respectively. The first electric motor 210 andsecond electric motor 215 can also act as generators such as duringregenerative braking. In such a situation, the first inverter 212 andsecond inverter 217 act as rectifiers by converting the AC electricalpower from the first electric motor 210 and second electric motor 215,respectively, to DC power that is supplied to the ESS 115. In theillustrated example, the first inverter 212 and second inverter 217include combined inverter-rectifiers that at least convert DC to AC andAC to DC.

As can be seen in FIG. 2, a transmission 205 further includes a firstgear train 220. The first gear train 220 is located at the output end ofthe first electric motor 210 which is located on the end of the electricpowertrain 200 that is opposite to the drive shaft 125. The firstelectric motor 210 and second electric motor 215 are sandwiched betweenthe first gear train 220 and second gear train 270. Among other things,this sandwiched relationship simplifies assembly and enhancesperformance. For instance, this sandwiched configuration in which thefirst electric motor 210 and second electric motor 215 are locatedbetween the first gear train 220 and second gear train 270 aids inretrofitting the powertrain system 105 to pre-existing vehicle designs.With the gearing as the ends, multiple electric powertrains 200 can bedaisy chained together so as to share gearing between the electricpowertrains 200. Moreover, all or some of the equipment related to themotors can be shared or concentrated in one area. The first electricmotor 210 and second electric motor 215 can also be packed closelytogether so as to conserve space. The first gear train 220 includes afirst planetary gear 225. As depicted, the first planetary gear 225 hasa sun gear 230 that is attached to the first electric motor 210, one ormore planet gears 235 engaged to orbit around the sun gear 230, and aring gear 240 that surrounds the planet gears 235. The planet gears 235engage both the sun gear 230 and ring gear 240. The planet gears 235 aresecured to a first carrier 245.

The electric powertrain 200 further has a first output shaft 250 thatconnects the first carrier 245 of the first planetary gear 225 to thedrive shaft 125. Proximal to the drive shaft 125, the clutch engagementmember 295 extends radially from the first output shaft 250. Asillustrated, the first output shaft 250 extends in a longitudinaldirection through the first electric motor 210, second electric motor215, and a second output shaft 277. The first output shaft 250 extendsin a concentric manner with the second output shaft 277. The firstelectric motor 210 and second electric motor 215 in one example arerespectively secured to the first planetary gear 225 and second outputshaft 277 via spline type connections. The first electric motor 210 canhave an uninterrupted connection to the drive shaft 125 via the firstplanetary gear 225 and first output shaft 250, if so desired.

The transmission 205 further includes a Selectable One-Way Clutch(“SOWC”) 255 that is able to engage and disengage the ring gear 240 suchthat ring gear 240 is able to be stationary or rotate. In theillustrated example, the SOWC 255 includes a clutch engagement member260 configured to engage the ring gear 240 of the first planetary gear225 and a clutch actuator 265 that selectively engages the clutchengagement member 260 with the ring gear 240 to provide torque from thefirst electric motor 210 to the first output shaft 250. The clutchactuator 265 is operatively coupled to the controller 110 so that thecontroller 110 is able to control the operation of the SOWC 255.

When the clutch actuator 265 of the SOWC 255 disengages the clutchengagement member 260 from the ring gear 240, the ring gear 240 is ableto rotate or orbit around the sun gear 230 in the first planetary gear225. With the ring gear 240 in this disengaged state in which the ringgear 240 is able to move, the first carrier 245 remains generallystationary even when the first electric motor 210 rotates or appliestorque to the sun gear 230 of the first planetary gear 225.Consequently, torque is not transferred from the first electric motor210 to the drive shaft 125. In another embodiment, when torque from thefirst electric motor 710 is not required, the first electric motor 710can be shut down. This prevents the rotation of the first electric motor710. As a result, no torque is provided to the drive shaft 125. On theother hand, when the controller 110 via the clutch actuator 265 engagesthe clutch engagement member 260 with the ring gear 240, relativemovement of the ring gear 240 is prevented. Having the ring gear 240fixed allows the first carrier 245 to rotate as the first electric motor210 rotates the sun gear 230 which in turn allows torque to betransferred from the first electric motor 210 to the drive shaft 125along the first output shaft 250. The first electric motor 210 is againa high speed motor. The first planetary gear 225 reduces the outputspeed of the first electric motor 210 such that the speed of the firstoutput shaft 250 can generally match the speed of the lower speed,second electric motor 215, if needed.

A second gear train 270 and a clutch 285 in the electric powertrain 200operate in a similar fashion as described before. The controller 110 viaa clutch actuator 292 shifts a dog clutch 290 between neutral, firstrange, and second range positions so that the second electric motor 215is able to provide different torques (or not) to a clutch engagementmember 295 that are combined with the torque from the first electricmotor 210 at the drive shaft 125. When the dog clutch 290 is in aneutral position, the second electric motor 215 does not supply power tothe drive shaft 125. In such a case, the first electric motor 210 cansupply all of the power to the drive shaft 125, if required. Once more,the first electric motor 210 can also act as a generator duringregenerative braking so as to recharge the ESS 115. The dog clutch 290engages a first range member 297 to place the clutch 285 in the firstrange position where the second electric motor 215 is able to providehigher torques through a second planetary gear 275 connected by a secondcarrier 280 and first range member 297 to the drive shaft 125. The dogclutch 290 shifts to the second range position by engaging a secondrange member 299. At the second range position, the second electricmotor 215 provides a torque that is lower than when at the first rangeposition, but the speed is higher. While the first electric motor 210 isa high speed motor, the output speed of the first electric motor 210 isreduced by the first planetary gear 225, and the second electric motor215 is a low speed motor such that the first gear train 220 is notrequired to reduce the speed of the output from the electric powertrain200. This configuration in turn allows the use of two different, ornon-interchangeable, motors that have different power profiles such thatthe first electric motor 210 and second electric motor 215 cumulativelycan operate more efficiently.

FIG. 3 shows a diagram of another example of an electric powertrain 300that can be used in the vehicle 100 of FIG. 1, and FIG. 4 shows across-sectional view of the electric powertrain 300. The electricpowertrain 300 shares a number of components and functions in commonwith the one described before. For the sake of brevity as well asclarity, these common features will not be described in great detailbelow, but please refer to the previous discussions of these features.

As depicted, the electric powertrain 300 includes a multiple motorcontinuous power transmission 302. The transmission 302 of the electricpowertrain 300 includes a first electric motor 305 with a first inverter306 and a second electric motor 307 with a second inverter 308. Thefirst inverter 306 is electrically connected between the ESS 115 and thefirst electric motor 305, and the second inverter 308 is electricallyconnected between the ESS 115 and the second electric motor 307. Thefirst inverter 306 and second inverter 308 convert the direct current(DC) from the ESS 115 to alternating current (AC) in order to power thefirst electric motor 305 and second electric motor 307, respectively.The first electric motor 305 and second electric motor 307 can also actas generators such as during regenerative braking. In such a situation,the first inverter 306 and second inverter 308 convert the AC electricalpower from the first electric motor 305 and second electric motor 307,respectively, to DC power that is supplied to the ESS 115. In oneexample, the first electric motor 305 and second electric motor 307 arethe same type of electric motor such that both motors generally providethe same speed and torque output within normal manufacturing tolerances.The first electric motor 305 and second electric motor 307 in one formare interchangeable with one another. The first electric motor 305 andsecond electric motor 307 in one form are both high speed electricmotors. In one specific example, the first electric motor 305 and secondelectric motor 307 are the same type of high speed electric motor havingrated speeds of at least 5,000 rpm, and more particularly, the firstelectric motor 305 and second electric motor 307 each has a rated speedof at least 10,600 rpm, a rated peak power of at least 390 hp, a ratedcontinuous power of at least 150 hp, a rated continuous torque of atleast 240 lb-ft, and a rated peak torque of at least 310 lb-ft.

As can be seen in FIGS. 3 and 4, the electric powertrain 300 includes afirst gear train 309 and a second gear train 310. The first gear train309 is located at the output end of the first electric motor 305 and isproximal to the drive shaft 125. The first gear train 309 includes afirst planetary gear 397 with a sun gear 390. Located opposite thesecond electric motor 307, on the other side of the drive shaft 125 isthe second gear train 310. The second gear train 310 includes a secondplanetary gear 315 with a second carrier 320.

In the illustrated example, the transmission 302 includes a first outputshaft 325, a second output shaft 330, and a third output shaft 335 thatextend in a longitudinal direction in the electric powertrain 300. Thefirst output shaft 325 and second output shaft 330 are hollow so as toreceive the third output shaft 335. The third output shaft 335 extendsin a concentric manner inside the first output shaft 325 and secondoutput shaft 330. The second gear train 310 and second planetary gear315 in one example are respectively secured to the first output shaft325 and second output shaft 330 via a spline type connection of thetypes described before.

As shown, the first output shaft 325 and third output shaft 335 aredirectly connected to the sun gear 390 of the first planetary gear 397.The second output shaft 330 has an interruptible connection with thefirst output shaft 325 through a first clutch 340 that selectivelyconnects the second output shaft 330 to the first output shaft 325. Toprovide a compact design, the first clutch 340 is located or sandwichedin between the first electric motor 305 and second electric motor 307.In the illustrated example, the first clutch 340 includes a singleposition type dog clutch 345, but other types of clutches can be used inother variations. The dog clutch 345 includes a clutch collar 350 and aclutch actuator 355 that is configured to move the clutch collar 350 ina longitudinal direction to engage and disengage the second output shaft330 from the first output shaft 325. The clutch actuator 355 of thefirst clutch 340 is operatively connected to the controller 110 so thatthe controller 110 is able to control the first clutch 340. In thedepicted example, the first output shaft 325 has a clutch engagementmember 360 and the second output shaft 330 has a range member 365, andthe clutch collar 350 of the dog clutch 345 selectively engages anddisengages the range member 365 of the second output shaft 330 from theclutch engagement member 360 of the first output shaft 325. In otherwords, the first output shaft 325 and second output shaft 330 form aninterruptible split shaft design that can be selectively connectedtogether so that the torque from the second gear train 310 and secondplanetary gear 315 can be combined together.

At the end opposite the range member 365, the second output shaft 330 isconnected to the second planetary gear 315. Like in the other examples,the second planetary gear 315 includes the sun gear 390, one or moreplanet gears 392, and a ring gear 395 generally arranged in a concentricmanner relative to one another. The second output shaft 330 in thedepicted example is connected to the second planetary gear 315 at thesun gear 390. The second planetary gear 315 is in turn connected to thethird output shaft 335 through the second carrier 320. Through thesecond carrier 320, the second planetary gear 315 is able to providetorque to the first output shaft 325 which in turn is provided to thesun gear 390 of the first gear train 309.

The transmission 302 further includes a second clutch 370 that engagesthe second planetary gear 315. In the illustrated example, the secondclutch 370 includes a Selectable One-Way Clutch (“SOWC”) 375. The SOWC375 includes a clutch engagement member 380 configured to engage thering gear 395 of the second planetary gear 315 and a clutch actuator 385that selectively engages the clutch engagement member 380 with the ringgear 395 to change the gear ratio for the power supplied by the secondplanetary gear 315 or disconnects the second electric motor 307. Theclutch actuator 385 of the SOWC 375 is operatively connected to thecontroller 110 so that the controller 110 is able to control the secondclutch 370. By controlling the operation of the first clutch 340 andsecond clutch 370, the controller 110 is able to change and control thespeed and torque supplied by the second planetary gear 315 to the firstgear train 309. In one form, the first clutch 940 and the second clutch970 work together to attain the first range position. To attain thefirst range position, the SOWC 975 is engaged to the ring gear 260 byactuation of the clutch actuator 985. At this time, the first clutch 940is disengaged from the clutch engagement member 960 so that the firstoutput shaft 925 and the second output shaft 930 are disconnected. Toattain the second range position, the SOWC 975 is disengaged from thering gear 260 by actuation of the clutch actuator 985. This allows thering gear 260 to freewheel. At this time, the first clutch 940 isactuated by the clutch actuator 955 to engage with the clutch engagementmember 960. This connects the first output shaft 925 and the secondoutput shaft 930.

As should be recognized, the second gear train 310 in FIGS. 3 and 4operates in a similar fashion to the first planetary gear 225 in FIG. 2.When the clutch engagement member 380 of the SOWC 375 engages the ringgear 395, the second gear train 310 reduces the speed and increases thetorque supplied to the third output shaft 335 from the second electricmotor 307. When the clutch engagement member 380 is disengaged from thering gear 395, no torque is provided via the second gear train 310. Toprovide torque from the second electric motor 307, the controller 110via the dog clutch 345 connects the range member 365 of the secondoutput shaft 330 to the clutch engagement member 360 of the first outputshaft 325. In these as well as other operational scenarios, the firstgear train 309 reduces the speed of the output provided by the firstelectric motor 305 and/or second electric motor 307 which are high speedmotors.

FIG. 5 shows a diagram of another example of the powertrain system 105of FIG. 1. The powertrain system 105 shares a number of components andfunctions in common with the ones described before (see e.g., FIGS. 2and 3). For the sake of brevity as well as clarity, these commonfeatures will not be described in great detail below, but please referto the previous discussion.

As depicted, the powertrain system 105 includes a multiple motorcontinuous power transmission 505. The transmission 505 of thepowertrain system 105 includes the first electric motor 210 with thefirst inverter 212 and the second electric motor 215 with the secondinverter 217. The first inverter 212 is electrically connected betweenthe ESS 115 and the first electric motor 210, and the second inverter217 is electrically connected between the ESS 115 and the secondelectric motor 215. The first inverter 212 and second inverter 217convert the direct current (DC) from the ESS 115 to alternating current(AC) in order to power the first electric motor 210 and second electricmotor 215, respectively. The first electric motor 210 and secondelectric motor 215 can also act as generators such as duringregenerative braking. In such a situation, the first inverter 212 andsecond inverter 217 convert the AC electrical power from the firstelectric motor 210 and second electric motor 215, respectively, to DCpower that is supplied to the ESS 115. In one example, the firstelectric motor 210 and second electric motor 215 are the same type ofelectric motor such that both motors generally provide the same speedand torque output within normal manufacturing tolerances. The firstelectric motor 210 and second electric motor 215 in one form are bothhigh speed electric motors, and in another form, the first electricmotor 210 and second electric motor 215 are both low speed electricmotors. In alternative variations, the first electric motor 210 andsecond electric motor 215 can be different such that one for example isa high speed motor and the other is a low speed motor.

The transmission 505 of the powertrain system 105 includes the firstgear train 309 of the type shown in FIG. 3, the second gear train 270 ofthe type shown in FIG. 2, and a third gear train 510. The first geartrain 309 is located downstream of the second electric motor 215 and isproximal to the drive shaft 125. The second gear train 270 is locatedjust upstream from the first gear train 309 sandwiched between thesecond electric motor 215 and the first gear train 309. The third geartrain 510 is located on the opposite side of the first electric motor210 and second electric motor 215 where a first output shaft 515 of thetransmission 505 meets the third gear train 510. The third gear train510 includes a third planetary gear 530 and a fourth planetary gear 535which are meshed and held in position by a third carrier 540. The thirdcarrier 540 is mounted to the transmission housing and does not move.Located between the fourth planetary gear 535 and a second clutch 525 isa first range member 555. The first range member 555 serves to engagethe second clutch 525 when in the first range positon. The third geartrain 510 also has a second range member 550 which serves to engage thesecond clutch 525 when in the second range position. Whether in thefirst or second range positon, the third gear train 510 has a clutchengagement member 545 to engage the second clutch 525 and transmit powerthrough the first output shaft 515. In the illustrated example, thefirst gear train 309 is in the form of the first planetary gear 397 asshown in FIG. 3, the second gear train 270 is in the form of the secondplanetary gear 275 as shown in FIG. 2, and the third gear train 510 isin the form of the third planetary gear 530 and the fourth planetarygear 535. The first electric motor 210 and second electric motor 215respectively have the first output shaft 515 and a second output shaft520 for providing rotational mechanical power. In the illustratedexample, the second output shaft 520 is hollow such that the firstoutput shaft 515 is able to extend through the second output shaft 520in a concentric manner.

The second gear train 270 and clutch 285 in the powertrain system 105operate as follows. The controller 110 via the clutch actuator 292shifts the clutch 285 between neutral, first range, and second rangepositions. This allows the second electric motor 215 to providedifferent output torques to the clutch engagement member 295 which arethen combined with the torque produced by the first electric motor 210through the third gear train 510 at the drive shaft 125. When the clutch285 is in the neutral position the second electric motor 215 does notsupply power to the drive shaft 125. In this case all of the outputpower is being supplied by the first electric motor 210. To place theclutch 285 into the first range positon the clutch actuator 292 movesthe clutch 285 to engage with the first range member 297. This allowsthe second electric motor 215 to provide higher torques to the driveshaft 125. The second range position is achieved by having the clutchactuator 292 move the clutch 285 to engage with the second range member299. In the second range position, the second electric motor 215 is ableto provide less torque than in the first range position, but the speedis higher. The first gear train 309 is made up of the first planetarygear 397 and is connected to the drive shaft 125 by the first carrier399. The first gear train 309 serves to reduce the speed of the outputprovided by the first electric motor 210 and/or the second electricmotor 215. The second gear train 270 is not connected to a clutch andtherefore is constantly in use.

The third gear train 510 and the second clutch 525 operate in a similarfashion to the second gear train 270 and clutch 285 described above. Thecontroller 110 via a second clutch actuator 527 shifts the second clutch525 between neutral, first range, and second range positions. Thisallows the first electric motor 210 to provide different output torquesto the clutch engagement member 545 which are then sent through thefirst output shaft 515 to the drive shaft 125. When the second clutch525 is in the neutral position, the torque runs through the first outputshaft 515 to the drive shaft 125 modified only by the first gear train309. To place the second clutch 525 into the first range positon, thesecond clutch actuator 527 moves the second clutch 525 to engage withthe first range member 555. This allows the first electric motor 210 toprovide higher torques through a third planetary gear 530 and a fourthplanetary gear 535 which are connected by the third carrier 540. Thesecond range position is achieved by having the second clutch actuator527 move the second clutch 525 to engage with the second range member550. In the second range position, the first electric motor 210 providesless torque than in the first range position, but the speed is higher.

Glossary of Terms

The language used in the claims and specification is to only have itsplain and ordinary meaning, except as explicitly defined below. Thewords in these definitions are to only have their plain and ordinarymeaning. Such plain and ordinary meaning is inclusive of all consistentdictionary definitions from the most recently published Webster'sdictionaries and Random House dictionaries. As used in the specificationand claims, the following definitions apply to these terms and commonvariations thereof identified below.

“About” with reference to numerical values generally refers to plus orminus 10% of the stated value. For example if the stated value is 4.375,then use of the term “about 4.375” generally means a range between3.9375 and 4.8125.

“And/Or” generally refers to a grammatical conjunction indicating thatone or more of the cases it connects may occur. For instance, it canindicate that either or both of two stated cases can occur. In general,“and/or” includes any combination of the listed collection. For example,“X, Y, and/or Z” encompasses: any one letter individually (e.g., {X},{Y}, {Z}); any combination of two of the letters (e.g., {X, Y}, {X, Z},{Y, Z}); and all three letters (e.g., {X, Y, Z}). Such combinations mayinclude other unlisted elements as well.

“Axis” generally refers to a straight line about which a body, object,and/or a geometric figure rotates or may be conceived to rotate.

“Clutch” generally refers to a device that engages and disengagesmechanical power transmission between two or more rotating shafts orother moving components. In one example, one shaft is typically attachedto an engine, motor, or other power source, which acts as the drivingmember, while the other shaft (i.e., the driven member) provides outputpower for work. While the motions involved are usually rotary motions,linear clutches are also used to engage and disengage components movingwith a linear or near linear motion. The clutch components can forinstance be engaged and disengaged through mechanical, hydraulic, and/orelectrical actuation. The clutches can include positive type clutchesand friction type clutches. Wet type clutches are typically immersed ina cooling lubrication liquid or other fluid, and dry clutches are notbathed in such liquids. Some non-limiting examples of clutches includecone clutches, centrifugal clutches, torque limiter clutches, axialclutches, disc clutches, dog clutches, and rim clutches, to name just afew.

“Contact” generally refers to a condition and/or state where at leasttwo objects are physically touching. For example, contact requires atleast one location where objects are directly or indirectly touching,with or without any other member(s) material in between.

“Controller” generally refers to a device, using mechanical, hydraulic,pneumatic electronic techniques, and/or a microprocessor or computer,which monitors and physically alters the operating conditions of a givendynamical system. In one non-limiting example, the controller caninclude an Allen Bradley brand Programmable Logic Controller (PLC). Acontroller may include a processor for performing calculations toprocess input or output. A controller may include a memory for storingvalues to be processed by the processor or for storing the results ofprevious processing. A controller may also be configured to accept inputand output from a wide array of input and output devices for receivingor sending values. Such devices include other computers, keyboards,mice, visual displays, printers, industrial equipment, and systems ormachinery of all types and sizes. For example, a controller can controla network or network interface to perform various network communicationsupon request. The network interface may be part of the controller, orcharacterized as separate and remote from the controller. A controllermay be a single, physical, computing device such as a desktop computeror a laptop computer, or may be composed of multiple devices of the sametype such as a group of servers operating as one device in a networkedcluster, or a heterogeneous combination of different computing devicesoperating as one controller and linked together by a communicationnetwork. The communication network connected to the controller may alsobe connected to a wider network such as the Internet. Thus a controllermay include one or more physical processors or other computing devicesor circuitry and may also include any suitable type of memory. Acontroller may also be a virtual computing platform having an unknown orfluctuating number of physical processors and memories or memorydevices. A controller may thus be physically located in one geographicallocation or physically spread across several widely scattered locationswith multiple processors linked together by a communication network tooperate as a single controller. Multiple controllers or computingdevices may be configured to communicate with one another or with otherdevices over wired or wireless communication links to form a network.Network communications may pass through various controllers operating asnetwork appliances such as switches, routers, firewalls or other networkdevices or interfaces before passing over other larger computer networkssuch as the Internet. Communications can also be passed over the networkas wireless data transmissions carried over electromagnetic wavesthrough transmission lines or free space. Such communications includeusing WiFi or other Wireless Local Area Network (WLAN) or a cellulartransmitter/receiver to transfer data.

“Controller Area Network” or “CAN” generally refers to a vehicle busstandard designed to allow microcontrollers, sensors, and/or otherdevices to communicate with each other in applications withoutnecessarily a host computer. CAN systems include a message-basedprotocol, designed originally for multiplex electrical wiring withinautomobiles, but is also used in many other contexts. A vehicle with aCAN system may normally, but not always, includes multiple ElectronicControl Units (ECUs) which can be also called nodes. These ECUs caninclude Engine Control Modules (ECMs) and Transmission Control Modules(TCMs) as well as other control units such as for airbags, antilockbraking/ABS, cruise control, electric power steering, audio systems,power windows, doors, mirror adjustment, battery and/or hybrid/electricrecharging systems, to name just a few. A CAN includes a multi-masterserial bus standard for connecting ECUs. The complexity of the ECU ornode can range from a simple Input/Output (I/O) device up to an embeddedcomputer with a CAN interface and software. The ECU or node can also actas a gateway allowing a general purpose computer to communicate over aninterface, such as via a USB and/or Ethernet port, to the devices on theCAN network. Each ECU usually, but not always, includes a centralprocessing unit, a CAN controller, and transceiver. The CAN systems canfor example include low speed CAN (128 Kbps) under the ISO 11898-3standard, high speed CAN (512 Kbps) under the ISO 11898-2 standard, CANFD under the ISO 11898-1 standard, and single wire CAN under the SAEJ2411 standard.

“Dog Clutch” generally refers to a type of positive clutch that couplesand decouples at least two rotating shafts or other rotating mechanicalcomponents by an interference type connection. The two parts of theclutch are designed such that one will push the other, thereby causingboth to rotate at the same speed with no (or very minimal) slippage.Typically, but not always, one part of the dog clutch includes a seriesof teeth or other protrusions that are configured to mate with anotherpart of the dog clutch that includes corresponding recesses forreceiving the teeth or protrusions. Unlike friction clutches that allowslippage, dog clutches are used where slip is undesirable and/or theclutch is not used to control torque. Without slippage, dog clutches arenot affected by wear in the same manner as friction clutches.

“Downstream” generally refers to a direction or relative location thatis the same as where power flows in a system.

“Electric Motor” generally refers to an electrical machine that convertselectrical energy into mechanical energy. Normally, but not always,electric motors operate through the interaction between one or moremagnetic fields in the motor and winding currents to generate force inthe form of rotation. Electric motors can be powered by direct current(DC) sources, such as from batteries, motor vehicles, and/or rectifiers,or by alternating current (AC) sources, such as a power grid, inverters,and/or electrical generators. An electric generator can (but not always)be mechanically identical to an electric motor, but operate in thereverse direction, accepting mechanical energy and converting themechanical energy into electrical energy.

“Energy Storage System” (ESS) or “Energy Storage Unit” generally refersto a device that captures energy produced at one time for use at a latertime. The energy can be supplied to the ESS in one or more forms, forexample including radiation, chemical, gravitational potential,electrical potential, electricity, elevated temperature, latent heat,and kinetic types of energy. The ESS converts the energy from forms thatare difficult to store to more conveniently and/or economically storableforms. By way of non-limiting examples, techniques for accumulating theenergy in the ESS can include: mechanical capturing techniques, such ascompressed air storage, flywheels, gravitational potential energydevices, springs, and hydraulic accumulators; electrical and/orelectromagnetic capturing techniques, such as using capacitors, supercapacitors, and superconducting magnetic energy storage coils;biological techniques, such as using glycogen, biofuel, and starchstorage mediums; electrochemical capturing techniques, such as usingflow batteries, rechargeable batteries, and ultra batteries; thermalcapture techniques, such as using eutectic systems, molten salt storage,phase-change materials, and steam accumulators; and/or chemical capturetechniques, such as using hydrated salts, hydrogen, and hydrogenperoxide. Common ESS examples include lithium-ion batteries and supercapacitors.

“Gear Train” generally refers to a system of gears that transmit powerfrom one mechanical component to another. For example, a gear train caninclude a combination of two or more gears, mounted on rotating shafts,to transmit torque and/or power. As one non-limiting example, the geartrain for instance can include a planetary gearset.

“High Speed Motor” generally refers to a motor that has a ratedoperating speed of at least 5,000 rpm (revolutions per minute) withoutthe use of gear trains or other similar equipment for changing speed.

“Integrally Formed” generally refers to being formed as or fused into asingle piece without needing some form of connection or attachment.

“Interruptible Connection” generally refers to a mechanical linkagebetween two mechanical components that has the ability to breakcontinuity during normal operation such that the components can bemechanically disconnected and reconnected if so desired. Whendisconnected, the components are unable to provide mechanical power toone another. The interruptible connection can include multiplecomponents such as multiple shafts and gears that engage with oneanother. The interruptible connection includes at least one mechanism,such as a clutch, that is designed to disconnect and reconnect themechanical linkage between the components during normal operation.

“Inverter” or “Power Inverter” generally refers to an electronic deviceand/or circuitry that at least converts direct current (DC) toalternating current (AC). Certain types of inverters can further includea rectifier that converts AC to DC such that the inverter and rectifierfunctions are combined together to form a single unit that is sometimesreferred to as an inverter. The inverter can be entirely electronic ormay be a combination of mechanical devices, like a rotary apparatus, andelectronic circuitry. The inverter can further include static typeinverters that do not use moving parts to convert DC to AC.

“Lateral” generally refers to being situated on, directed toward, orcoming from the side. “Longitudinal” generally relates to length orlengthwise dimension of an object, rather than across.

“Low Speed Motor” generally refers to a motor that has a rated operatingspeed of less than 5,000 rpm (revolutions per minute) without the use ofgear trains or other similar equipment for changing speed.

“Means For” in a claim invokes 35 U.S.C. § 112(f), literallyencompassing the recited function and corresponding structure andequivalents thereto. Its absence does not, unless there otherwise isinsufficient structure recited for that claim element. Nothing herein orelsewhere restricts the doctrine of equivalents available to thepatentee.

“Mounted” means physically attached to or held in place by. This may beby fasteners, adhesives, conduits, brackets, over molded plastic, orotherwise.

“Multiple” is generally synonymous with the term “plurality” and refersto more than one, or by extension, two or more.

“Planetary Gear” or “Planetary Gearset” generally refers to a system ofat least two gears mounted so that the center of at least one gearrevolves around the center of the other. In other words, the planetarygear includes a system of epicyclic gears in which at least one gearaxis revolves about the axis of another gear. In one example, a carrierconnects the centers of the two gears and rotates to carry one gear,which is called a planet gear, around the other, which is commonlycalled a sun gear. Typically, but not always, the planet and sun gearsmesh so that their pitch circles roll without slip. A point on the pitchcircle of the planet gear normally traces an epicycloid curve. In onesimplified case, the sun gear is fixed and the one or more planet gearsroll around the sun gear. In other examples, an epicyclic gear train canbe assembled so the planet gear rolls on the inside of the pitch circleof a fixed, outer gear ring, or ring gear, that is sometimes called anannular gear. In this case, the curve traced by a point on the pitchcircle of the planet gear is a hypocycloid. A planetary gear istypically used to transfer large torque loads in a compact form.

“Positive Clutch” generally refers to a type of clutch that is designedto transmit torque without slippage such as through a mechanicalinterference type connection. Some examples of positive clutches includejaw clutches (e.g., square or spiral jaw clutches) and dog clutches.

“Powertrain” generally refers to devices and/or systems used totransform stored energy into kinetic energy for propulsion purposes. Thepowertrain can include multiple power sources and can be used innon-wheel-based vehicles. By way of non-limiting examples, the storedenergy sources can include chemical, solar, nuclear, electrical,electrochemical, kinetic, and/or other potential energy sources. Forexample, the powertrain in a motor vehicle includes the devices thatgenerate power and deliver the power to the road surface, water, and/orair. These devices in the powertrain include engines, motors,transmissions, drive shafts, differentials, and/or final drivecomponents (e.g., drive wheels, continuous tracks, propeller, thrusters,etc.).

“Predominately” is synonymous with greater than 50%.

“Rated Continuous Power” or “Continuous Rated Power” generally refer toan amount of energy or work provided per unit of time (i.e., power) anelectric motor will produce without interruption for a rated speed, at arated torque, and at a rated voltage for the electric motor. In otherwords, the rated continuous power is usually the power that the electricmotor can produce for a long period of time at the rated speed and therated torque without damaging the electric motor.

“Rated Operating Speed” or “Rated Speed” generally refers to a velocity(i.e., speed) an electric motor will rotate when producing a ratedcontinuous power at a supplied rated voltage for the electric motor.Typically, but not always, the rated operating speed is measured interms of Revolutions Per Minute (rpm). Generally speaking, the ratedoperating speed is the prescribed rpm at which the motor operates,keeping the mechanical stability and efficiency of the electric motor inmind. The rated voltage and rated horsepower respectively refer to themaximum voltage and horsepower (hp) where the motor can operateefficiently without being damaged. The value for the rated operatingspeed will be slightly less than a synchronous speed of the electricmotor due to a decrease in speed caused by adding a load (i.e., slip orspeed loss). For instance, most alternating current (AC) inductionmotors with synchronous speeds of 1800 RPM will have normally have ratedspeeds ranging between about 1720 and about 1770 RPM depending on theamount of slip. Some newer high or energy-efficient electric motors willtend to have rated operating speeds towards a higher end of the range.

“Rated Continuous Torque” or “Continuous Rated Torque” generally referto a magnitude of twisting force, or torque, an electric motor willproduce without interruption for a rated speed and at a rated voltagefor the electric motor. In other words, the rated continuous torque isusually a torque that the electric motor can output for a long period oftime at the rated speed without damaging the electric motor. Typically,this value is generated close to the maximum speed of the motor.

“Selectable One-Way Clutch” (SOWC) generally refers to a type of clutchthat is able to be controlled to lock in at least one rotationaldirection. One-way clutches are usually (but not always) designed totransfer torque or lock when rotated in one direction and to allowrotational movement or free-wheel when rotated in the oppositedirection. The SOWC is a type of one-way clutch that can be used tocontrol when and/or in which direction the rotational motion is lockedor able to rotate freely. By way of a non-limiting example, the SOWC canbe activated to lock so as to transfer torque when torque is applied inone rotational direction and facilitate free-wheel or slipping movementin the opposite rotational direction. In other variations, the SOWC canbe controlled at times to facilitate free-wheel motion in bothrotational directions or locked to allow torque transfer in bothrotational directions. Alternatively or additionally, the SOWC can becontrolled to switch or change the locked and freewheel rotationaldirections. For example, the SOWC under one operating condition can belocked when rotated in a counterclockwise and free-wheel spin in theclockwise direction, and under other conditions, the SOWC can beswitched so that the SOWC is locked in the clockwise direction andfreewheel spin in the counterclockwise direction. Some non-limitingexamples of SOWC designs include roller, sprag, spiral, and mechanicaldiode type designs. The SOWC can be controlled or actuated in a numberof ways such as through mechanical and/or electrical actuation. Forinstance, the SOWC can be actuated with hydraulic, pneumatic, and/orelectrical type actuators to name just a few.

“Substantially” generally refers to the degree by which a quantitativerepresentation may vary from a stated reference without resulting in anessential change of the basic function of the subject matter at issue.The term “substantially” is utilized herein to represent the inherentdegree of uncertainty that may be attributed to any quantitativecomparison, value, measurement, and/or other representation.

“Symmetric” or “Symmetrical” generally refer to a property of somethinghaving two sides or halves that are the same relative to one another,such as in shape, size, and/or style. In other words, symmetricdescribes something as having a mirror-image quality.

“Synchronizer” or “Synchronizer Mechanism” (“Synchromesh”) generallyrefer to a device that includes a cone clutch and a blocking ring whichbrings the speeds of a gear and a gear selector to the same speed usingfriction. In one example, before the teeth of the gear and gear selectorcan engage, the cone clutch engages first which in turn brings the gearselector and gear to the same speed using friction. Untilsynchronization occurs, the teeth of the gear and the gear selector areprevented from making contact by the blocking ring. When synchronizationoccurs, the friction on the blocking ring is relieved and the blockingring twists slightly. With this twisting motion, grooves or notches arealigned that allow further passage of the gear selector which brings theteeth together.

“Transmission” generally refers to a power system that providescontrolled application of mechanical power. The transmission uses gearsand/or gear trains to provide speed, direction, and/or torqueconversions from a rotating power source to another device.

“Upstream” generally refers to a direction or relative location that isopposite from where power flows in a system.

“Vehicle” generally refers to a machine that transports people and/orcargo. Common vehicle types can include land based vehicles, amphibiousvehicles, watercraft, aircraft, and space craft. By way of non-limitingexamples, land based vehicles can include wagons, carts, scooters,bicycles, motorcycles, automobiles, buses, trucks, semi-trailers,trains, trolleys, and trams. Amphibious vehicles can for example includehovercraft and duck boats, and watercraft can include ships, boats, andsubmarines, to name just a few examples. Common forms of aircraftinclude airplanes, helicopters, autogiros, and balloons, and spacecraftfor instance can include rockets and rocket-powered aircraft. Thevehicle can have numerous types of power sources. For instance, thevehicle can be powered via human propulsion, electrically powered,powered via chemical combustion, nuclear powered, and/or solar powered.The direction, velocity, and operation of the vehicle can be humancontrolled, autonomously controlled, and/or semi-autonomouslycontrolled. Examples of autonomously or semi-autonomously controlledvehicles include Automated Guided Vehicles (AGVs) and drones.

The term “or” is inclusive, meaning “and/or”.

It should be noted that the singular forms “a,” “an,” “the,” and thelike as used in the description and/or the claims include the pluralforms unless expressly discussed otherwise. For example, if thespecification and/or claims refer to “a device” or “the device”, itincludes one or more of such devices.

It should be noted that directional terms, such as “up,” “down,” “top,”“bottom,” “lateral,” “longitudinal,” “radial,” “circumferential,”“horizontal,” “vertical,” etc., are used herein solely for theconvenience of the reader in order to aid in the reader's understandingof the illustrated embodiments, and it is not the intent that the use ofthese directional terms in any manner limit the described, illustrated,and/or claimed features to a specific direction and/or orientation.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges, equivalents, and modifications that come within the spirit ofthe inventions defined by the following claims are desired to beprotected. All publications, patents, and patent applications cited inthis specification are herein incorporated by reference as if eachindividual publication, patent, or patent application were specificallyand individually indicated to be incorporated by reference and set forthin its entirety herein.

Reference Numbers 100 vehicle 105 powertrain system 110 controller 115ESS 120 CAN 125 drive shaft 130 propulsion system 135 wheels 140 powercables 200 electric powertrain 205 transmission 210 first electric motor212 first inverter 215 second electric motor 217 second inverter 220first gear train 225 first planetary gear 230 sun gear 235 planet gears240 ring gear 245 first carrier 250 first output shaft 255 SOWC 260clutch engagement member 265 clutch actuator 270 second gear train 275second planetary gear 277 second output shaft 280 second carrier 285clutch 290 dog clutch 292 clutch actuator 295 clutch engagement member297 first range member 299 second range member 300 electric powertrain302 transmission 305 first electric motor 306 first inverter 307 secondelectric motor 308 second inverter 309 first gear train 310 second geartrain 315 second planetary gear 320 second carrier 325 first outputshaft 330 second output shaft 335 third output shaft 340 first clutch345 dog clutch 350 clutch collar 355 clutch actuator 360 clutchengagement member 365 range member 370 second clutch 375 SOWC 380 clutchengagement member 385 clutch actuator 390 sun gear 392 planet gears 395ring gear 397 first planetary gear 399 first carrier 505 transmission510 third gear train 515 first output shaft 520 second output shaft 525second clutch 527 second clutch actuator 530 third planetary gear 535fourth planetary gear 540 third carrier 545 clutch engagement member 550second range member 555 first range member

What is claimed is:
 1. A powertrain system, comprising: a first geartrain; a first electric motor connected to an output via the first geartrain, wherein the first electric motor has an uninterrupted connectionto the output, wherein the uninterrupted connection is a mechanicallinkage that lacks a break in continuity; a second gear train; a secondelectric motor connected to the output via the second gear train;wherein the first electric motor and the second electric motor aresandwiched between the first gear train and the second gear train;wherein the first electric motor and the second electric motor lack anygear train therebetween; wherein power is supplied to the output solelythrough the first and second electric motors; a clutch, wherein theclutch is configured to selectively connect the second electric motor tothe first electric motor; wherein clutch is moveable between at least aneutral position, a first range position, and a second range position;wherein the clutch at the neutral position disconnects the secondelectric motor from the first electric motor; wherein the clutch at thefirst range position increases torque supplied from the second electricmotor; and wherein the clutch at the second range position decreasestorque suppled from the second electric motor.
 2. The powertrain systemof claim 1, wherein the second electric motor has an interruptibleconnection to the output.
 3. The powertrain system of claim 2, whereinthe interruptible connection includes the clutch configured to couplethe second electric motor to the output.
 4. The powertrain system ofclaim 3, wherein the clutch is a positive clutch.
 5. The powertrainsystem of claim 3, wherein the clutch is a dog Clutch.
 6. The powertrainsystem of claim 3, wherein the clutch is located between the firstelectric motor and the second electric motor.
 7. The powertrain systemof claim 3, wherein the clutch is located downstream of the firstelectric motor and the second electric motor at the output.
 8. Thepowertrain system of claim 1, wherein the second gear train is locatedupstream from the first electric motor and the second electric motor. 9.The powertrain system of claim 8, further comprising: a SelectableOne-Way Clutch (SOWC) is located upstream from the first electric motorand the second electric motor at the second gear train.
 10. Thepowertrain system of claim 8, wherein the second electric motor islocated upstream relative to the first electric motor.
 11. Thepowertrain system of claim 1, wherein the first gear train is locatedupstream from the first electric motor and the second electric motor.12. The powertrain system of claim 11, further comprising: a SelectableOne-Way Clutch (SOWC) is located upstream of the first electric motorand the second electric motor at the first gear train.
 13. Thepowertrain system of claim 11, wherein the first electric motor islocated upstream relative to the second electric motor.
 14. Thepowertrain system of claim 1, wherein the first gear train includes afirst planetary gear.
 15. The powertrain system of claim 1, wherein thefirst and second electric motors rotate about a common axis of rotation.16. A powertrain system, comprising: a first gear train; a firstelectric motor connected to an output via the first gear train; a secondgear train; a second electric motor connected to the output via thesecond gear train; wherein the first electric motor has an uninterruptedconnection to the output and the second electric motor has aninterruptible connection to the output; wherein the second gear train islocated upstream from the first electric motor and the second electricmotor; wherein the uninterrupted connection is a mechanical linkage thatlacks a break in continuity; wherein the interruptible connectionincludes a clutch disposed between the first electric motor and thesecond electric motor; wherein the clutch is a dog clutch; wherein thepower is supplied to the output solely through the first and secondelectric motors; and wherein the first electric motor and the secondelectric motor lack any gear train therebetween.
 17. The powertrainsystem of claim 16, wherein the interruptible connection includes aclutch configured to couple the second electric motor to the output. 18.The powertrain system of claim 16, wherein the first electric motor andthe second electric motor are sandwiched between a first gear train anda second gear train.
 19. The powertrain system of claim 18, furthercomprising: a Selectable One-Way Clutch (SOWC) is located upstream fromthe first electric motor and the second electric motor at the secondgear train.
 20. A powertrain system, comprising: a first gear train; afirst electric motor connected to an output via the first gear train; asecond gear train; a second electric motor connected to the output viathe second gear train; wherein the first electric motor has anuninterrupted connection to the output and the second electric motor hasan interruptible connection to the output; wherein the first gear trainis located upstream from the first electric motor and the secondelectric motor; wherein the uninterrupted connection is a mechanicallinkage that lacks a break in continuity; wherein the interruptibleconnection includes a clutch configured to couple the second electricmotor to the output; wherein the clutch is a dog clutch; a SelectableOne-Way Clutch (SOWC) is located upstream of the first electric motorand the second electric motor at the first gear train; wherein the firstelectric motor is located upstream relative to the second electricmotor; wherein the power is supplied to the output solely through thefirst and second electric motors; and wherein the first electric motorand the second electric motor lack any gear train therebetween.
 21. Thepowertrain system of claim 20, wherein the interruptible connectionincludes a clutch configured to couple the second electric motor to theoutput.
 22. The powertrain system of claim 20, wherein the firstelectric motor and the second electric motor are sandwiched between afirst gear train and a second gear train.
 23. The powertrain system ofclaim 22, further comprising: a Selectable One-Way Clutch (SOWC) islocated upstream of the first electric motor and the second electricmotor at the first gear train.
 24. The powertrain system of claim 22,wherein the first electric motor is located upstream relative to thesecond electric motor.
 25. The powertrain system of claim 1, wherein:the first electric motor and the second electric motor are differentfrom one another; the first electric motor is a high speed motor with arated operating speed of at least 5,000 rpm; and the second electricmotor is a low speed motor with a rated operating speed of less than5,000 rpm.
 26. The powertrain system of claim 14, wherein the secondgear train includes a second planetary gear.
 27. The powertrain systemof claim 26, further comprising: a first output shaft connected to thefirst electric motor; wherein the first output shaft is connected to thefirst planetary gear; wherein the second planetary gear includes a sungear, a ring gear, and one or more planet gears engaged between the sungear and the ring gear; wherein second gear train includes a first rangemember connected to the planet gears of the second planetary gear; asecond output shaft connected to the second electric motor; wherein thesecond output shaft has a second range member; wherein the clutch at thefirst range position engages the first range member to increase thetorque from the second electric motor; and wherein the clutch at thesecond range position engages the second range member to reduce thetorque from the second electric motor.
 28. The powertrain system ofclaim 16, further comprising: a first output shaft connected to thefirst electric motor; a second output shaft connected to the secondelectric motor; a third output shaft; wherein the first output shaft andthe second output shaft are hollow; wherein the third output shaftextends in a concentric manner inside the first output shaft and thesecond output shaft; wherein the first gear train includes a firstplanetary gear; wherein the second gear train includes a secondplanetary gear; and wherein the clutch is configured to selectivelyconnect the first output shaft to the second output shaft.
 29. Thepowertrain system of claim 20, wherein: the first gear train includes afirst planetary gear; the second gear train includes a second planetarygear; the interruptible connection includes a clutch configured tocouple the second electric motor to the output; the clutch is moveablebetween at least a neutral position, a first range position, and asecond range position; the clutch at the neutral position disconnectsthe second electric motor from the first electric motor; and the clutchat the first range position engages the second planetary gear toincrease torque from the second electric motor.